Indoor lighting for palms

[Mark_NoVA]

I bring a lot of palms indoors for the period when temperatures can approach freezing, which lasts about 6 months here. Although I have some nice windowed areas, as I'm accumulating more palms and they're getting bigger, I'm running out of natural-light space and looking into getting supplemental lighting. All I want to do is have the palms survive healthily--don't need a lot of growth. Most of the palms I'm bringing in are still small, and have origins in rain forests where they don't get a lot of light when young. Unfortunately, the information I can find about plant lighting is for plants that want more light than these palms.

Here's what I can gather about different types of plant lighting:

High-Output T5 Fluorescent

2x the light of standard fluorescent, but still much less than HID lamps. Wide color spectrum. Energy-efficient. Main question is whether or not they are bright enough--they need to be 8-12" away from seedlings (plants in general) for growth.

Metal-Halide HID lamps

Much brighter; spectrum similar to daylight, a little more to the blue and less to the red side, so better for foliage than flowering. Supposedly more energy-efficient in terms of really-bright light than fluorescents, but unsure if palms need that bright of light. More attractive lighting than HPS.

High-Pressure Sodium HID lamps

Color spectrum not that similar to sunlight, more to the red spectrum and useful for flowering; plants may stretch and become leggy. More energy-efficient than Metal-Halide.

Other issues:

Supposedly the quality of the reflector and where ballasts are located can be an issue. Can get track systems, where the HID light moves back and forth.

The palms have different heights, so the lighting can't be that close to some of them--makes me unsure if the High-Output T5 Fluorescent would be bright enough.

Of the HID lamps, metal-halide sounds better because of the color spectrum. However, I don't want to spend a ton of $$ on electricity, and having just a few of these lamps to cover the whole potted-palm areas could add up to a lot.

What recommendations do you have, for types of lighting and specific brands/places to buy?

What are your experiences?

[DoomsDave]

Generally, flourescent beats incandescent, in every way. You get a much more complete spectrum.

But, nothing subs for the Sun (worship the Sun God, Goddes, Hermaphroditic Diety).

Full-sun palms will need both incandescent (far red) and flourescent to be really happy.

For a long time, but over the winter, flourescent lights work great.

dave

[Neofolis]

I use metal hallides, but what is best will really depend on the situation. The first thing I would say is make sure you are getting as much natural light as possible, because trying to substitute it is expensive and not always easy. The problem with artificial light is that, if something is twice the distance away, it will only get half the light, so something 2 feet away will only get half of the light that something one foot away is getting, assuming there are no obstructions. This means the lights have to be close to the plants to be of any use, but not too close, because then heat becomes an issue. When you have plants of varying heights and differing growth rates, you have a choice of forever moving things or getting very little of the available light to the plants. If the lights are on a rail system, you need to think, how long will each plant be getting a reasonable amount of light and if you have several plants, one light may only be close to each plant for a fairly short time. Some people prefer fluorescents, because their large surface area means they can be close to many plants at the same time, but if you do that, none of the plants are receiving all of the light from the lamps, just a small amount from the part they are near to. This is less of an issue if the temperatures are kept low enough for the plants to not grow, but with the lights adding heat, it may be more difficult to keep the temperatures down.

If this is going to be in an area that has frequent human use fluorescent will be much easier to live with. With the MH or HPS lamps anything 600W or above is seriously bright and could be quite a distraction for humans.

[sonoranfans]

  Neofolis said:

I use metal hallides, but what is best will really depend on the situation. The first thing I would say is make sure you are getting as much natural light as possible, because trying to substitute it is expensive and not always easy. The problem with artificial light is that, if something is twice the distance away, it will only get half the light, so something 2 feet away will only get half of the light that something one foot away is getting, assuming there are no obstructions. This means the lights have to be close to the plants to be of any use, but not too close, because then heat becomes an issue. When you have plants of varying heights and differing growth rates, you have a choice of forever moving things or getting very little of the available light to the plants. If the lights are on a rail system, you need to think, how long will each plant be getting a reasonable amount of light and if you have several plants, one light may only be close to each plant for a fairly short time. Some people prefer fluorescents, because their large surface area means they can be close to many plants at the same time, but if you do that, none of the plants are receiving all of the light from the lamps, just a small amount from the part they are near to. This is less of an issue if the temperatures are kept low enough for the plants to not grow, but with the lights adding heat, it may be more difficult to keep the temperatures down.

If this is going to be in an area that has frequent human use fluorescent will be much easier to live with. With the MH or HPS lamps anything 600W or above is seriously bright and could be quite a distraction for humans.

I have also used metal halides, they are the best indoors, except for small seedlings. I have a "sun systems" 400W metal halide light and have used it successfully on 3 species of archontos, saw palmettos, dypsis baronii, dypsis leptcheillois. For small seedlings, the T5 fluorescents are best as they dont burn the leaflets so easily, but once the seedlings get a little larger, the metal halide is best. Metal halides have hot spots(of higher intensity) due to the imaging of the filament and can burn small seedlings if you put them too close. T5's have no filament and have very even lighting so they can put put within about 12" of a small seedling. T5's are the most efficient fluroescents and have the highest lumen density per watt of all fluorescents and run cooler for similar wattage. Sodium vapor lights are not good, except for flowering plants(they are best for flowers), they lead to weak stems and elongation, been there done that, I should have done the research first. Do some google keyword research and you can verify all this for yourself. Light intensity varies with the square of the distance, this means that leaflets 2x further away will get 4x less light, not 2x less. The metal halides put out more light per square meter so they will get you notably better growth on seedlings that are say, greater than 15" tall or so. You may need several metal halide lights, or a whole bank of T5 fluorescents depending on the size and number of your seedlings. When using metal halides, be careful about distance to leaflets, especially on young palms. Start at 3' min distance and move closer to 18" as they grow larger. watch closely for signs of leaf burn.

If you use indoor grow lights, try to move your palms into sunlight as often as possible. You can increase the intensity of the artificial light to your palms by using some aluminum foil, hung vertically all around your palms. this will help get more light intensity to your lower leaflets. Also, Metal halide lighting can be very variable, for example, all 400W systems are not equal, some bulb and ballast combos can actually put out 30% more lumens than others. It is true that you often get what you pay for in these systems. If you have alot of palms, consider one or more 1000W systems. (1) 400W MH system is good for about a 3' by 3' area. You will find the prices pretty steep( I paid $260 for a good 400W system). T5's fluorescents are also as pricey per lumen, and will not sustain larger seedlings as effectively. Get them back into direct sun as soon as possible and and often as possible. the problem with all interior lighting is that it just isnt nearly as bright as natural sunlight.

One final word, watch the humidity as your palms can dry out under these lights in winter especially if you have forced air heat. You might consider a humidifier and a humidistat.

PM me if I can be of any further help.

[joe_OC]

  Mark_NoVA said:

I bring a lot of palms indoors for the period when temperatures can approach freezing, which lasts about 6 months here. Although I have some nice windowed areas, as I'm accumulating more palms and they're getting bigger, I'm running out of natural-light space and looking into getting supplemental lighting. All I want to do is have the palms survive healthily--don't need a lot of growth. Most of the palms I'm bringing in are still small, and have origins in rain forests where they don't get a lot of light when young. Unfortunately, the information I can find about plant lighting is for plants that want more light than these palms.

Here's what I can gather about different types of plant lighting:

High-Output T5 Fluorescent

2x the light of standard fluorescent, but still much less than HID lamps. Wide color spectrum. Energy-efficient. Main question is whether or not they are bright enough--they need to be 8-12" away from seedlings (plants in general) for growth.

Metal-Halide HID lamps

Much brighter; spectrum similar to daylight, a little more to the blue and less to the red side, so better for foliage than flowering. Supposedly more energy-efficient in terms of really-bright light than fluorescents, but unsure if palms need that bright of light. More attractive lighting than HPS.

High-Pressure Sodium HID lamps

Color spectrum not that similar to sunlight, more to the red spectrum and useful for flowering; plants may stretch and become leggy. More energy-efficient than Metal-Halide.

Other issues:

Supposedly the quality of the reflector and where ballasts are located can be an issue. Can get track systems, where the HID light moves back and forth.

The palms have different heights, so the lighting can't be that close to some of them--makes me unsure if the High-Output T5 Fluorescent would be bright enough.

Of the HID lamps, metal-halide sounds better because of the color spectrum. However, I don't want to spend a ton of $$ on electricity, and having just a few of these lamps to cover the whole potted-palm areas could add up to a lot.

What recommendations do you have, for types of lighting and specific brands/places to buy?

What are your experiences?

Hey Mark,

I have been playing with all sorts of lights when I was into reef-keeping to keep the corals happy. This is my take on the different lighting technologies you have listed:

T5 Fluorescent: Great choice if energy cost and heat are an issue for you. They are one of the most efficient bulbs on the market. You can pack a lot of them in to get more intensity and it will draw less energy than MH. They come in different colors as well so I would recommend 6500 Kelvin bulbs

Metal Halide Lamps: MH will come closest to the sun's spectrum and intensity if you use 6500 Kelvin bulbs. I used 10000 Kelvin bulbs to get more "blue" in the light. The two negatives with MH is A LOT of heat and $$$ electricity bills. If those are not issues, then go with MH. You can find MH with different ballasts. I would recommend an electronic ballast.

High-Pressure Sodium HID lamps: Would definitely go with the other lighting option over HPS because it does not come near the color spectrum needed by the plants.

LED is the latest technology coming into the market for aqua-culturing and indoor farming. They have been able to mix the different light spectrum to provide more red that stimulates more growth. Seems to be very promising with great growth results with lowest heat and lowest energy draw.

HTH's,

Joe

[xerophyte_nyc]

T-5 Fluorescents have great light but is really best for young or small plants so that the leaf surfaces can get as close as possible to the light. These are probably not the best option for larger palms as it would be extremely difficult to push out enough light.

HID lamps are probably the best bet, they can be hung at a distance and still achieve 1500+ foot candles, which should suffice for most palms.

I use 175W Metal halide bulbs that fit into a standard socket + reflector. I just wire it to an electronic ballast and away we go. The self-reflective bulbs can be had for $15 on eBay, and you can get a socket at Home Depot, just make sure it is ceramic to be able to take the heat. 175W ballasts can be had for about $70.

Next, you need to figure out a way to mount the lights. You can get one of those cheap reflector clamp-on shop lights, or get fancy with a swivelier. The choice is yours.

A couple of these mounted above will make for excellent supplemental lighting.

By the way, any wattage grow light will pretty much give off the same heat. In a 1000W HID light for example, the heat is focused because all the energy is directed to a small bulb. A 1000W T-5 setup with equivalent lumens will give off almost the same heat except that it is spread over the greater surface area so it appears to be less but really is not.

[Big Tex]

I have good luck with the Metal-Halide HID lamps. Just make sure you get plenty of wattage.

[joe_OC]

It's not about light intensity or wattage that plants need to grow. It's about the right light spectrum.

"Usable Light Energy of Artificial Lighting compared to Sunlight

Useable light energy for plant growth is measured in Micro-Einstein’s ( micro-mols of photons per meter squared per second). The sunlight reaching our plant is approximately 2,200 micro-Einstein’s on a cloud-less day and 170 micro-Einstein’s on a very cloudy day.

For indoor growing under artificial lighting a range of 200 to 500 micro-Einsteins is considered by experts at NASA to be minimal energy level for plant growth.

The higher the bulb wattage the further away the plant must be from the light source to prevent environmental heat stress that can cause the plant to transpire too quickly. Excessive transpiring can dehydrate plants leading to wilting and poor growth. Likewise, the further the plant is from the light source the less available useable energy is delivered to the plant. The indoor grower most tune light energy resources as well as other environmental variables for optimal growing conditions."

Here is a great article on what NASA is doing:

http://www.space.com/businesstechnology/te...ing_010926.html

Turns out that Red and Blue are the two main colors in the spectrum that are needed for plants to grow... LED allows you to control what spectrum of light you can give your plants at a low wattage so there are minimal heat created.

[Mark_NoVA]

Interesting article about NASA and the LED light research! Once they can mass-produce brighter LED bulbs, they'll replace other bulbs because of their longevity and much smaller electricity usage. I have some LED light bulbs. The problem is, they're weaker than incandescent bulbs. Since incandescent bulbs are too weak for grow lights, I wonder how well LED grow lights currently can work. I'd guess (but don't know) that currently they would have to be used like fluorescent bulbs, placed very close to the plants.

Looking more at Metal Halide lamps, it looks like electronic ballasts would be important for me. (Older/cheaper ballasts are magnetic.) Supposedly, the electronic ballasts are quieter (very important for me, as these are in the home and I hate buzzing electronic equipment), can save a bit on electricity, and prolong the life of bulbs with gentler (yet faster) startups. Some common electronic ballasts used for horticultural applications include Lumatek, Sunlight Supply's Galaxy, and Future-Brite. There's a question of what power to get--400, 250, 150/175 watts. Galaxy has some dual ballasts--2 250s or 150s in one, to save some $$.

Then, you have the choice of different reflectors. There's a bunch of them and it's a little hard for me to differentiate among them. Sunlight Supply's Sun System series seems to be pretty well-regarded.

There's also the bulb choice. Some newer metal halide bulbs get some more of the red spectrum, getting them closer to daylight spectrum. A couple of more-common ones seem to be Eye Hortilux Blue and AgroSun Gold (less $$).

There's also a more-DIY route like you were describing, xerophyte_nyc, but I was a little unsure of the quality/appropriateness of the various components I could find.

So anyone know about these different electronic ballasts, reflectors and bulbs? I'm leaning toward 1 400W or 2 250W MH HIDs with electronic ballasts right now, perhaps with AgroSun Gold bulbs.

[edit]

That's interesting about how light energy is me measured--saw a disscusion at Apogee Instruments which makes quantum meters to measure it; also got info at Wikipedia.

[sonoranfans]

  Mark_NoVA said:

Interesting article about NASA and the LED light research! Once they can mass-produce brighter LED bulbs, they'll replace other bulbs because of their longevity and much smaller electricity usage. I have some LED light bulbs. The problem is, they're weaker than incandescent bulbs. Since incandescent bulbs are too weak for grow lights, I wonder how well LED grow lights currently can work. I'd guess (but don't know) that currently they would have to be used like fluorescent bulbs, placed very close to the plants.

Looking more at Metal Halide lamps, it looks like electronic ballasts would be important for me. (Older/cheaper ballasts are magnetic.) Supposedly, the electronic ballasts are quieter (very important for me, as these are in the home and I hate buzzing electronic equipment), can save a bit on electricity, and prolong the life of bulbs with gentler (yet faster) startups. Some common electronic ballasts used for horticultural applications include Lumatek, Sunlight Supply's Galaxy, and Future-Brite. There's a question of what power to get--400, 250, 150/175 watts. Galaxy has some dual ballasts--2 250s or 150s in one, to save some $$.

Then, you have the choice of different reflectors. There's a bunch of them and it's a little hard for me to differentiate among them. Sunlight Supply's Sun System series seems to be pretty well-regarded.

There's also the bulb choice. Some newer metal halide bulbs get some more of the red spectrum, getting them closer to daylight spectrum. A couple of more-common ones seem to be Eye Hortilux Blue and AgroSun Gold (less $$).

There's also a more-DIY route like you were describing, xerophyte_nyc, but I was a little unsure of the quality/appropriateness of the various components I could find.

So anyone know about these different electronic ballasts, reflectors and bulbs? I'm leaning toward 1 400W or 2 250W MH HIDs with electronic ballasts right now, perhaps with AgroSun Gold bulbs.

Sounds like you are on the right track, Mark. One thing I like about my sunsystems system is that the reflector has a glass lens(protects against UV burn), and is ventilated. One small 4" fan and a little 4" hose puts the heat in the attic. And if you read keeping the bulb cool prolongs life. The reef trade has alot of good articles on MH systems. All bulbs are not equal, some are better than others. Keep researching it. LEDs are getting close to being practical in the reef tank app, meaning that they are not far away.

[joe_OC]

For electronic ballasts, check out the manufacturers for the reef keeping industry as well:

Ice Cap and Blueline are very good products. I don't know how their pricing compares to traditional horticulture MH e-ballasts...

University of Purdue announced recently that they have created a new manufacturing process that uses a silicon based substrate instead of saphire. LED will be the new incandescent in the near future...

[protempsfish]

So what about the incandescent bulbs that claim to increase plant growth? You can get them at home depot and it states on the package that they increase plant growth in indoor situations. Are they useless?!

[Mark_NoVA]

protempsfish, from what I read, incandescent isn't typically considered, probably because it's so expensive in terms of amount of light per watt. You might also run into issues of being close enough to give enough light, but being too close to burn the plants.

  sonoranfans said:

One thing I like about my sunsystems system is that the reflector has a glass lens(protects against UV burn), and is ventilated. One small 4" fan and a little 4" hose puts the heat in the attic.

Tom, do you remember which reflector you got? Would you get the same one again? What kind of fan did you get?

[Guest fossel]

I have a 430 hps with inhanced blue spectrum and I grow plumarias and I bring in my areca vestiaria in the cold weeks ,so far so good

[sonoranfans]

  Mark_NoVA said:

protempsfish, from what I read, incandescent isn't typically considered, probably because it's so expensive in terms of amount of light per watt. You might also run into issues of being close enough to give enough light, but being too close to burn the plants.

  sonoranfans said:

One thing I like about my sunsystems system is that the reflector has a glass lens(protects against UV burn), and is ventilated. One small 4" fan and a little 4" hose puts the heat in the attic.

Tom, do you remember which reflector you got? Would you get the same one again? What kind of fan did you get?

Here is my system , Mark. Its been awhile so I dont remember who I bought it from. But the supplier had a 4" fan as an option that inserts into the 6" duct(another option).

http://www.bghydro.com/BGH/customkititems....PS04SS2&eq=

I like my reflector, but there are others that are probably just as good or better. I would recomment a ventilated reflector, though, as it will help increase bulb life/keep the palms cooler. When I was researching reef aquarium systems a few years back, independent university research strongly recommended matching the ballast to the bulb to increase bulb life as well. For this reason, I bought one of the recommended bulbs for the system from the supplier. My wife likes to use the light for flowers, so I bought a switchable MH/HPS ballast, it will take either metal halide or HPS. If I was buying the light for palms only, I would not buy that ballast, only one for MH. Now that my seedlings are larger, I dont bring them in for the winter, so my wife has taken it over .

[palmsrgreat]

I suggested a friend of mine install a couple of solar tubes on his garage which lead to the basement. He gets an incredible amount of light and is able to store palms in the warmer area where his furnace is. Plus no additional costs!

[tjwalters]

  palmsrgreat said:

I suggested a friend of mine install a couple of solar tubes on his garage which lead to the basement. He gets an incredible amount of light and is able to store palms in the warmer area where his furnace is. Plus no additional costs!

Exactly what I was thinking. My parents had some of them installed and they are incredibly intense. The installer had to wear special sunglass when installing them.

[Mark_NoVA]

Thanks, I didn't know there were things like that different from skylights!

  tjwalters said:

  palmsrgreat said:

I suggested a friend of mine install a couple of solar tubes on his garage which lead to the basement. He gets an incredible amount of light and is able to store palms in the warmer area where his furnace is. Plus no additional costs!

Exactly what I was thinking. My parents had some of them installed and they are incredibly intense. The installer had to wear special sunglass when installing them.

[Mark_NoVA]

After spending far too much time researching this, I'm looking at a 400W Metal Halide lamp. My reasoning is that since artificial light weakens very quickly, a stronger lamp is good for taller plants (say 3-4' as compared to around 1'), so a 400w MH lamp might be more appropriate than a H5 fluorescent system or a 175/250W HID system.

Reflector: Sunlight Supply 'Super Horizontal Reflector' Since storing young rainforest palms over the winter needs less light than most growing situations, where people are looking for a lot of active growth, I'm choosing a reflector that spreads light over a wider area and consequently less intensely than others. A wider area helps with the number of plants to be brought in, too!

Hot Spot Diffuser: The Equalizer This seems to be a good item to add to the type of reflector. Bulbs can have a hot spot directly underneath them, so this hot spot diffuser spreads out the light that comes directly downwards from the bulb.

Ballast: Galaxy 400W Electronic Ballast As far as I can tell, this and the Lumatek electronic ballast are pretty comparable; I'm just going with the brand that also makes the reflector. As mentioned above, electronic ballasts are quieter than magnetic ballasts, and supposedly conserve electricity or make the bulb brighter, prolong bulb life with gentler startups, and also start up in about 1 minute instead of 20.

Bulb: AgroSun Gold A bulb that adds some red spectrum to give the MH a broader spectrum. Not as good as the Eye Hortilux Blue, but I didn't want to spend a lot more on that bulb.

Needed to get a timer and hanging system to go with it too.

When finding a good place to buy these things, a problem is that most if not all of these places seem to be dominated by sales to indoor pot growers, and you wonder if some of them are shady or well-run. I tried to go with what appeared to be a larger business to be safe. (Also, a lot of places don't sell the big reflector I chose--probably too big for pot-growing closets ). So I ordered from a place at www.bghydro.com. The web page conked out after I pressed the 'order' button, which is always scary! So today I called to see if the order went through, was on hold for a long time, told the order didn't grow through, transferred to a person to order this time, went through a very lengthy process, the ballast wasn't in stock, and finally told that I couldn't get the discount web price. So, nothing ordered yet.

[sonoranfans]

  Mark_NoVA said:

After spending far too much time researching this, I'm looking at a 400W Metal Halide lamp. My reasoning is that since artificial light weakens very quickly, a stronger lamp is good for taller plants (say 3-4' as compared to around 1'), so a 400w MH lamp might be more appropriate than a H5 fluorescent system or a 175/250W HID system.

Reflector: Sunlight Supply 'Super Horizontal Reflector' Since storing young rainforest palms over the winter needs less light than most growing situations, where people are looking for a lot of active growth, I'm choosing a reflector that spreads light over a wider area and consequently less intensely than others. A wider area helps with the number of plants to be brought in, too!

Hot Spot Diffuser: The Equalizer This seems to be a good item to add to the type of reflector. Bulbs can have a hot spot directly underneath them, so this hot spot diffuser spreads out the light that comes directly downwards from the bulb.

Ballast: Galaxy 400W Electronic Ballast As far as I can tell, this and the Lumatek electronic ballast are pretty comparable; I'm just going with the brand that also makes the reflector. As mentioned above, electronic ballasts are quieter than magnetic ballasts, and supposedly conserve electricity or make the bulb brighter, prolong bulb life with gentler startups, and also start up in about 1 minute instead of 20.

Bulb: AgroSun Gold A bulb that adds some red spectrum to give the MH a broader spectrum. Not as good as the Eye Hortilux Blue, but I didn't want to spend a lot more on that bulb.

Needed to get a timer and hanging system to go with it too.

When finding a good place to buy these things, a problem is that most if not all of these places seem to be dominated by sales to indoor pot growers, and you wonder if some of them are shady or well-run. I tried to go with what appeared to be a larger business to be safe. (Also, a lot of places don't sell the big reflector I chose--probably too big for pot-growing closets ). So I ordered from a place at www.bghydro.com. The web page conked out after I pressed the 'order' button, which is always scary! So today I called to see if the order went through, was on hold for a long time, told the order didn't grow through, transferred to a person to order this time, went through a very lengthy process, the ballast wasn't in stock, and finally told that I couldn't get the discount web price. So, nothing ordered yet.

Wow, sounds like you had a PIA type day with that.

this link doesnt seem to cater to the pot growers( no "hydroponics"), and may be more reliable.

http://www.specialty-lights.com/901339.html

I bought my(600W) timer from a reef tank site(there are tons on the web) that advertized on EBAY. Fans are available at most reef tank sites as well. the reef aquarium trade is big business, but the lights are made especially for aquariums.

By the way, yes the larger lights are better for taller palms. A 175w is almost useless in growing corals in a 2' deep reef tank. For alot of large palms (3-4') I would consider a 1000W light.

Edited October 24, 2008 by sonoranfans

[joe_OC]

Mark,

Have you checked Craigslist, under the farm and garden area? It's amazing the different lighting set ups people are selling on there, at least for me in So Cal...

[Mark_NoVA]

Finally got it ordered!

Craigslist doesn't have any grow lights listed out here. That's funny there's a lot in SoCal.

I called the Specialty-Lights place but didn't get a return call from a knowledgeable person in several days.

Looked at a couple of reef-lighting places but the fixtures seemed slightly different.

Called a place called GrowCo that had some good recommendations on Garden Watchdog, and immediately got in touch with a very knowledgable person. He'd just run experiments comparing the 2 systems I asked about (the setup above vs a dual 250W system). So, ordered from there--hopefully it'll all be fine.

Decided not to go with the hot spot diffuser. Supposedly reduces the lumens a tiny bit at the expense of spreading the light about evenly and allowing the reflector to get closer. Instead, I'll put the plants wanting the most light directly under the light.

Oh yeah, I have to re-shingle the roof anyway, so I'm looking at those solar tubes as well.

[Ricanstructed]

Aw man...this looks like it was a great thread THIRTEEN years ago lol. Would love to hear some of you guy's opinions on this topic now that LED has entered the building in a major way.

[PashkaTLT]

I have experience growing indoors using both HPS & LED. LED matches or exceeds efficiency of HPS lumen/watt-wise. Also, LED is not as hot as HPS. I love HPS, I had great results with it, but I feel like LED is winning now.

[sonoranfans]

The LED lights are more efficient, generate a lot less heat, and last far longer without a notable shift in the emitted spectrum when compared to HPS or Metal Halide.  Reef lighting for fish tanks is designed to deliver a light balance preferred by corals (water absorbs the red region).    The weakness of LED's is that they lose intensity faster with distance than the others, so lower leaves get proportionately less light.   LED's also need to be placed closer to the vegetative material and with the PAR(photosynthetically active radiation) drop off with distance being greater, they are so not good for the taller plants.  Still compared to the others LED's are the best all around indoor grow light.  They wont heat up your room or tank like the others and they will burn for 60k hrs and draw less current for the PAR they deliver.

[PashkaTLT]

  On 4/16/2023 at 2:31 PM, sonoranfans said:

The weakness of LED's is that they lose intensity faster with distance than the others, so lower leaves get proportionately less light. 

Expand  

This is a myth. I just tested this with my luxmeter on my LED & ESL bulbs and the intensity decreases absolutely the same, down to a couple of percent difference.

And as you said, LED allows to be placed closer, so it will be cheaper to run the LED fixture even if the bulbs have the same lumens.

In my experience, taller plants benefit greatly from additional, smaller bulbs on lower levels. I.e., say 100-150W light on the top and a couple of 20-30W bulbs at the middle of the plant.

Edited April 17, 2023 by PashkaTLT

[sonoranfans]

  On 4/16/2023 at 11:54 PM, PashkaTLT said:

This is a myth. I just tested this with my luxmeter on my LED & ESL bulbs and the intensity decreases absolutely the same, down to a couple of percent difference.

And as you said, LED allows to be placed closer, so it will be cheaper to run the LED fixture even if the bulbs have the same lumens.

In my experience, taller plants benefit greatly from additional, smaller bulbs on lower levels. I.e., say 100-150W light on the top and a couple of 20-30W bulbs at the middle of the plant.

Expand  

Have you measured HPS? I am also talking larger lighting syustems LED bar lights are recognized as the best LED lighting lkast I checked.  Our greenhhouses never used ESL lights, but we have used compact fluorescence, LED, Metal Halide and HPS.  LED lighting is highly variable, even the optics  can get complicated for those who are interested.   https://www.ledgrowlightsdepot.com/blogs/blog/led-grow-light-optics-explained  You have to pay to get a good LED lights as the better more efficient LEDs are more expensive than the cheaper ones.

[PashkaTLT]

I'm sorry @sonoranfans, I meant CFL, not ESL (English is not my native language).

I haven't compared to HPS yesterday, as I don't have any HPS now...

If you have a lux meter you can compare lux values say 1.5 ft and 3ft from HPS and do the same with LED and see if they decrease differently.

[sonoranfans]

  On 4/17/2023 at 7:22 PM, PashkaTLT said:

I'm sorry @sonoranfans, I meant CFL, not ESL (English is not my native language).

I haven't compared to HPS yesterday, as I don't have any HPS now...

If you have a lux meter you can compare lux values say 1.5 ft and 3ft from HPS and do the same with LED and see if they decrease differently.

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It will depend on the LED optical design as you can see from the article.  CFL is an inferior grow light to either metal halide HPS or LED bar arrays.